[AMDGPU] Require at least protected visibility for certain symbols

[scott.linder]

Summary

This allows the global visibility controls to be restrictive while still populating the dynamic symbol table where required. Depends in-part on a patch to apply global symbol visibility to declarations, although this patch is conservatively correct without that change.

[scott.linder]

Add missing flag to tests

[scott.linder]

Update option name

[scott.linder]

Update option name

[scott.linder]

Ping

[scott.linder]

Ping

[yaxunl]

LGTM. Thanks!

lib/CodeGen/CodeGenModule.cpp

LangAS ExpectedAS =
       D ? D->getType().getAddressSpace()
         : (LangOpts.OpenCL ? LangAS::opencl_global : LangAS::Default);
   assert(getContext().getTargetAddressSpace(ExpectedAS) ==
          Ty->getPointerAddressSpace());
   if (AddrSpace != ExpectedAS)
     return getTargetCodeGenInfo().performAddrSpaceCast(*this, GV, AddrSpace,
                                                        ExpectedAS, Ty);
 
+  if (GV->isDeclaration())
+    getTargetCodeGenInfo().setTargetAttributes(D, GV, *this);
+
   return GV;
 }
 
 llvm::Constant *
 CodeGenModule::GetAddrOfGlobal(GlobalDecl GD,
                                ForDefinition_t IsForDefinition) {
   const Decl *D = GD.getDecl();
   if (isa<CXXConstructorDecl>(D))

lib/CodeGen/TargetInfo.cpp

public:
   createEnqueuedBlockKernel(CodeGenFunction &CGF,
                             llvm::Function *BlockInvokeFunc,
                             llvm::Value *BlockLiteral) const override;
   bool shouldEmitStaticExternCAliases() const override;
   void setCUDAKernelCallingConvention(const FunctionType *&FT) const override;
 };
 }
 
+static bool requiresAMDGPUProtectedVisibility(const Decl *D,
+                                              llvm::GlobalValue *GV) {
+  if (GV->getVisibility() != llvm::GlobalValue::HiddenVisibility)
+    return false;
+
+  return D->hasAttr<OpenCLKernelAttr>() ||
+         (isa<FunctionDecl>(D) && D->hasAttr<CUDAGlobalAttr>()) ||
+         (isa<VarDecl>(D) && D->hasAttr<CUDADeviceAttr>());
+}
+
 void AMDGPUTargetCodeGenInfo::setTargetAttributes(
     const Decl *D, llvm::GlobalValue *GV, CodeGen::CodeGenModule &M) const {
+  if (requiresAMDGPUProtectedVisibility(D, GV)) {
+    GV->setVisibility(llvm::GlobalValue::ProtectedVisibility);
+    GV->setDSOLocal(true);
+  }
+
   if (GV->isDeclaration())
     return;
   const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D);
   if (!FD)
     return;
 
   llvm::Function *F = cast<llvm::Function>(GV);
 

test/CodeGenOpenCL/visibility.cl

+// RUN: %clang_cc1 -std=cl2.0 -fapply-global-visibility-to-externs -fvisibility default -triple amdgcn-unknown-unknown -S -emit-llvm -o - %s | FileCheck --check-prefix=FVIS-DEFAULT %s
+// RUN: %clang_cc1 -std=cl2.0 -fapply-global-visibility-to-externs -fvisibility protected -triple amdgcn-unknown-unknown -S -emit-llvm -o - %s | FileCheck --check-prefix=FVIS-PROTECTED %s
+// RUN: %clang_cc1 -std=cl2.0 -fapply-global-visibility-to-externs -fvisibility hidden -triple amdgcn-unknown-unknown -S -emit-llvm -o - %s | FileCheck --check-prefix=FVIS-HIDDEN %s
+
+// REQUIRES: amdgpu-registered-target
+
+// FVIS-DEFAULT:  @glob = local_unnamed_addr
+// FVIS-PROTECTED: @glob = protected local_unnamed_addr
+// FVIS-HIDDEN: @glob = hidden local_unnamed_addr
+int glob = 0;
+// FVIS-DEFAULT:  @glob_hidden = hidden local_unnamed_addr
+// FVIS-PROTECTED: @glob_hidden = hidden local_unnamed_addr
+// FVIS-HIDDEN: @glob_hidden = hidden local_unnamed_addr
+__attribute__((visibility("hidden"))) int glob_hidden = 0;
+// FVIS-DEFAULT:  @glob_protected = protected local_unnamed_addr
+// FVIS-PROTECTED: @glob_protected = protected local_unnamed_addr
+// FVIS-HIDDEN: @glob_protected = protected local_unnamed_addr
+__attribute__((visibility("protected"))) int glob_protected = 0;
+// FVIS-DEFAULT:  @glob_default = local_unnamed_addr
+// FVIS-PROTECTED: @glob_default = local_unnamed_addr
+// FVIS-HIDDEN: @glob_default = local_unnamed_addr
+__attribute__((visibility("default"))) int glob_default = 0;
+
+// FVIS-DEFAULT:  @ext = external local_unnamed_addr
+// FVIS-PROTECTED: @ext = external protected local_unnamed_addr
+// FVIS-HIDDEN: @ext = external hidden local_unnamed_addr
+extern int ext;
+// FVIS-DEFAULT:  @ext_hidden = external hidden local_unnamed_addr
+// FVIS-PROTECTED: @ext_hidden = external hidden local_unnamed_addr
+// FVIS-HIDDEN: @ext_hidden = external hidden local_unnamed_addr
+__attribute__((visibility("hidden"))) extern int ext_hidden;
+// FVIS-DEFAULT:  @ext_protected = external protected local_unnamed_addr
+// FVIS-PROTECTED: @ext_protected = external protected local_unnamed_addr
+// FVIS-HIDDEN: @ext_protected = external protected local_unnamed_addr
+__attribute__((visibility("protected"))) extern int ext_protected;
+// FVIS-DEFAULT:  @ext_default = external local_unnamed_addr
+// FVIS-PROTECTED: @ext_default = external local_unnamed_addr
+// FVIS-HIDDEN: @ext_default = external local_unnamed_addr
+__attribute__((visibility("default"))) extern int ext_default;
+
+// FVIS-DEFAULT: define amdgpu_kernel void @kern()
+// FVIS-PROTECTED: define protected amdgpu_kernel void @kern()
+// FVIS-HIDDEN: define protected amdgpu_kernel void @kern()
+kernel void kern() {}
+// FVIS-DEFAULT: define protected amdgpu_kernel void @kern_hidden()
+// FVIS-PROTECTED: define protected amdgpu_kernel void @kern_hidden()
+// FVIS-HIDDEN: define protected amdgpu_kernel void @kern_hidden()
+__attribute__((visibility("hidden"))) kernel void kern_hidden() {}
+// FVIS-DEFAULT: define protected amdgpu_kernel void @kern_protected()
+// FVIS-PROTECTED: define protected amdgpu_kernel void @kern_protected()
+// FVIS-HIDDEN: define protected amdgpu_kernel void @kern_protected()
+__attribute__((visibility("protected"))) kernel void kern_protected() {}
+// FVIS-DEFAULT: define amdgpu_kernel void @kern_default()
+// FVIS-PROTECTED: define amdgpu_kernel void @kern_default()
+// FVIS-HIDDEN: define amdgpu_kernel void @kern_default()
+__attribute__((visibility("default"))) kernel void kern_default() {}
+
+// FVIS-DEFAULT: define void @func()
+// FVIS-PROTECTED: define protected void @func()
+// FVIS-HIDDEN: define hidden void @func()
+void func() {}
+// FVIS-DEFAULT: define hidden void @func_hidden()
+// FVIS-PROTECTED: define hidden void @func_hidden()
+// FVIS-HIDDEN: define hidden void @func_hidden()
+__attribute__((visibility("hidden"))) void func_hidden() {}
+// FVIS-DEFAULT: define protected void @func_protected()
+// FVIS-PROTECTED: define protected void @func_protected()
+// FVIS-HIDDEN: define protected void @func_protected()
+__attribute__((visibility("protected"))) void func_protected() {}
+// FVIS-DEFAULT: define void @func_default()
+// FVIS-PROTECTED: define void @func_default()
+// FVIS-HIDDEN: define void @func_default()
+__attribute__((visibility("default"))) void func_default() {}
+
+void use() {
+    glob = ext + ext_hidden + ext_protected + ext_default;
+}